1. Field of the Invention
The present invention relates to an image forming apparatus such as a copy machine, a printer, a facsimile, or a complex machine having functions of these apparatuses, and particularly relates to an image forming apparatus allowing replacement of a development unit.
2. Description of Related Art
In an image forming apparatus such as a copy machine, a printer, a facsimile, or a complex machine having functions of these apparatuses, with progressing duration of use thereof, timely maintenance should be performed with respect to a drum unit including a photosensitive drum and a development unit including a development sleeve. For this reason, units requiring maintenance such as the drum unit and the development unit are so designed as to be individually removable from and insertable into a main body of the image forming apparatus.
For example, in an image forming apparatus in which four fan-shaped development units for respective colors of cyan, magenta, yellow, and black are disposed annularly, each of the development units is so designed as to be movable by rotation to a development position opposed to a photosensitive member. Each of the development units includes a development roller and a cover member movable between a position at which the cover member covers the development roller and a position at which the cover member has the development roller exposed. The cover member is so configured as to be opened in response to the rotation of each of the development units before it reaches to the development position and closed again after development is completed. In forming an image, each of the development units is moved by rotation to the development position at which toner is supplied from the development roller thereof to the photosensitive member, and thus an electrostatic latent image on the photosensitive member is developed into a toner image. In a case where any one of the development units is to be replaced for the purpose of developer replenishment or a maintenance check, the development unit in question is moved by rotation to an upper position in a main body of the apparatus, and then a cover of the apparatus disposed at an upper portion of the apparatus main body is opened, through which the development unit in question is taken out to the outside of the apparatus main body and a new development unit is mounted thereinto. At this time, the cover member is in a closed state, thereby preventing an operator replacing the development unit in question from soiling his/her hands with a developer contained therein or from spilling the developer.
With regard to an image forming apparatus such as a complex machine or a high-performance multi-functional printer, it is conventionally a serviceperson who provides maintenance work such as replacing a development unit. It has recently been more common, however, that a development unit or the like is replaced by a user instead of a serviceperson. In a case where a user replaces a development unit, it is necessary that a procedure for replacing the development unit be easy to understand and that measures be taken against possible erroneous operations such as dropping the development unit during the replacement. The above-described image forming apparatus, however, has been disadvantageous in that the replacement procedure is complex and hard to understand and in that a developer contained in the development unit might be scattered to the outside thereof if the development unit is accidentally dropped.